Multiple-plate clutch

Abstract

A multiple-plate clutch includes a first set of plates and a second set of plates, wherein one of the first and second set of plates is a set of internal plates and the other is a set of external plates, the plates of each set being mounted on a respective plate carrier so that they are axially displaceable but not rotatable relative to the respective plate carrier, wherein the first set is provided with a separating arrangement which extends axially over all of the plates of at least the first set of plates and is arranged in between each pair of adjacent plates of at least the first set of plates and is provided such that the separating arrangement is adapted to wedge in between the respective adjacent plates. The separating arrangement is provided with a force enhancement arrangement which adds a radial force to the separating arrangement, wherein the force enhancement arrangement is at least a resilient member acting upon the separating arrangement to enhance the wedging in between the respective adjacent plates.

Description

BACKGROUND AND SUMMARY[0001]The present invention relates to the field of friction clutches and especially multiple-plate friction clutches and separating means therefore.[0002]Stepped transmissions for vehicles are robust, compact and cost-effective products. A stepped transmission can be designed using gearwheels that rotate about fix axes, with planetary gear trains, or combinations thereof. A typical example of a fix-axes lay-out is shown in DE19821164A1. A modern transmission design using planetary gear trains can be seen in[0003]DE102005010210A1. Combinations of fix axes and planetary gear trains are found in, e.g., U.S. Pat. No. 5,351,569 and EP1211436A2. Basically, different gears are obtained by rotationally connecting different parts. This is done by shift clutches that can engage two rotating units. There are two main types of shift clutch; positively engaging tooth clutches and friction clutches. Tooth clutches have an “on-off” behaviour; they are either engaged or disen...

AI Technical Summary

Benefits of technology

This patent is about a new type of clutch that can be used in vehicles. The clutch uses a special design called a force enhancement means to increase the force on the clutch plates without adding extra weight. This means that the clutch can handle more power without needing a bigger size. The force enhancement means also helps to keep the clutch cool when it's being used. Overall, this new clutch design makes vehicles more powerful, comfortable, and fuel-efficient.

Problems solved by technology

In general, they can neither be engaged nor disengaged while transferring any significant amount of power.

Thus, at gear shifts several vehicle transmission designs with tooth clutches have an interruption of the power transfer between prime mover (engine) and driven wheels.

This is a rather slow process, which limits the slipping capability of dry plate clutches.

Moreover, the surfaces in contact are worn, implying a limited durability.

However, for more demanding applications, dry plate clutches are not suitable.

This has a considerable impact on the friction in the contacting surfaces.

Secondly, one actuation force can act on all surfaces.

However, the plurality of plates in a wet plate clutch will cause power losses in disengaged state when the rotating units have different rotational speeds.

Oil between the surfaces of two plates results in viscous drag.

Further, the plates may wobble and bounce against each other.

All this, separate or in combination, will give power losses.

A too large clearance may have a negative influence on the controllability of the clutch, though.

Some plates may “cling” to each other, causing large power losses.

Those tend to be rather costly, though, requiring a large number of small parts to handle and assemble.

A problem with the solution according to U.S. Pat. No. 4,117,919 is that the separation of the plates is not sufficient, in particular at low speed, where the centrifugal forces upon the separating means are low, such that substantial power losses still are present.

This effect can be minimised in that the mass of the separating means is increased, whereby an increase in weight is undesirable.

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